1. Field of the Invention
The present invention relates to a transport system for transporting semiconductor substrates or the like by a carrier attached to an endless driving medium. In particular, the present invention relates to a technique of allowing a carrier configured to carry articles such as semiconductor substrates or the like to load the articles from, or unload the articles to a hand of a station.
2. Description of the Related Art
According to the disclosure of U.S. Pat. No. 7,234,584, a plurality of carriers are attached to an endless belt, and the endless belt rotates in a circulating manner. Each of the carriers has a support surface for supporting a flange or the like of a semiconductor cassette, and the semiconductor cassette is loaded or unloaded using a hand of a station. Further, a sensor for detecting the carriers and an encoder for measuring a moving distance of the belt are provided to control the hand. In U.S. Pat. No. 7,234,584, the hand is activated immediately after detection of the carrier by the sensor. Therefore, the hand is activated at the same time during both of loading and unloading. However, if the hand is activated immediately after detection of the carrier, the delay in the signal processing appears as a control delay.